As tackiness agents, rubber-based tackiness agents, such as natural rubber and styrene-butadiene rubber, have been generally often used. However, for materials for use in processing steps during electronic device production, which require high heat resistance, acryl-based resin and silicone-based resin have been used.
The acryl-based resin, having high transparency as well, is often used as optical materials for flat displays, such as liquid crystal displays (refer to, e.g., Patent document 1). However, in the case where the acryl-based resin is left standing for a long time at a temperature greater than or equal to 200° C. and, furthermore, greater than or equal to 250° C., the acrylic resin itself decomposes and produces a volatile component; therefore, the acryl-based resin is insufficient in terms of heat resistance. The silicone-based resin has a wide working temperature range from low temperature to high temperature, and exhibits high heat resistance as compared with the acryl-based resin (refer to, e.g., Patent document 2). However, in the case of being left standing for a long time at a temperature greater than or equal to 250° C. and, furthermore, greater than or equal to 300° C., the silicone-based resin produces a volatile component due to decomposition or the like. Furthermore, since the silicone-based tackiness agent contains silicone components of low molecular weight, there is a problem of these components adversely affecting electronic component parts.
As resins having a heat resistance for 250° C. or higher, polyimide resin can be cited. As a polyimide resin to be used in use as an adhesive, for example, a siloxane-based polyimide resin in which siloxane-based diamine is copolymerized for the purpose of reducing production of gas during cure and developing excellent adhesiveness has been proposed (refer to, e.g., Patent document 3). Furthermore, for the purpose of enabling sticking a semiconductor adhesive tape at temperatures less than or equal to 300° C., a polysiloxane-based polyimide resin in which a diamine component is copolymerized with a polysiloxane-based diamine so that the glass transition temperature is 100 to 150° C. has been proposed (refer to, e.g., Patent document 4).